IV. 



RAINFALL. WIND. 



49 



Here the greater rainfall with southerly and south-westerly 

 winds, at Oxford, is very manifest ; these two directions yielding 

 more than half of the whole measured quantity. 



The number of days on which rain fell with these various winds 

 stands in even a higher ratio for the same five years : 



If the path of the wind over Oxford be laid down for a whole 

 year, from the Observatory Register, it will appear that at the end 

 of the period the atmosphere, after drifting in various directions, 

 has been displaced to the north-eastward a few thousand miles. 



The line of this annual drift has been determined by the Ead- 

 cliffe Observer, in the five years already referred to, as under : 



1861 S. 5iW. 



1862 S. siW. 



1863 S. 4oW. 



1864 S. i 9 W. 



1865 S. isW. 



in which a tendency to deviate eastward seems to be indicated 

 in the last three years b . 



The mean temperature of Oxford is something under 50. From 

 1862 to 1866 it averaged 49*8, the highest being 50-5, the lowest 

 49-0. During the same period the highest monthly mean was 

 62-9 (July, 1865), the lowest (January, 1865) 36-8. 



The mean temperature of evaporation differs from the air, on 

 an average of five years (1861-1865), 2' 7 8. This small differ- 

 ence may seem to justify the opinion, that the Oxford air is 

 a little damper than the average of the same latitude in Eng- 

 land ; but it is not uncommon with us to experience extremely 

 dry weather with differences between the dry and wet bulb of 



b In 1866 the mean direction was found to be S. 12 W. 



E 



